Just because you think “charity” means a certain thing, doesn’t mean that’s actually what it means. The legal definition of a charity includes all sorts of objectives, not just “benefiting those in need of help”. These include education, research, medicine, the military, ecology, emergency services, conservation, animal welfare, and so on.
A donkey sanctuary in Wales might only have five old donkeys, but it still has a charitable objective and meets public benefit requirements, even if it helps no humans in need and no-one in England ever gets to visit.
Schools that are charities are not businesses. They have no shareholders, cannot make a profit and must be structured legally as charities under Charity Commission guidelines. Everyone on these threads who keeps on saying “but they’re businesses” just makes it obvious that they have zero idea what a charity is OR what a business is.
It’s very easy to declaim what you think a charity is, but five minutes spent on the website of the Charity Commission actually looking it up would be more accurate and useful.